Method for constructing fire-stop collar assembly

ABSTRACT

A method of constructing a fire-stop collar assembly involves the steps of choosing a dummy pipe (14) at a factory which is an approximate size and shape of a pipe at an installment site on which a fire-stop collar assembly (10,54) produced by this method is to be mounted and, at the factory, wrapping an intumescent collar (34,82) into an approximate ring about an outer surface of the dummy pipe. Also, at the factory, a metallic band (32) is wrapped about the intumescent collar while the collar is wrapped about the dummy pipe and the end portions (36,38) are held together by a fastening device (40,56) while the collar is wrapped about the dummy pipe. Still at the factory, the dummy pipe is removed from the intumescent collar and the metallic band by longitudinal movement along the dummy pipe, thereby leaving rings of intumescent collar and the metallic band held together as an integral fire-stop collar assembly. Thereafter, the thusly assembled fire-stop collar assembly is transported away from the factory to be delivered to a separate installment site for permanent engagement on the pipe at the installment site. In one embodiment, the intumescent collar (82) is glued to the metallic band, and two longitudinal cuts (60,64 and 62,66) are placed along the intumescent collar, the longitudinal cuts being spaced approximately 180° from one another. The metallic band is compressed by a strap clamp (56) which can be removed and the fire-stop collar assembly can be easily opened to be placed on the pipe.

BACKGROUND OF THE lNVENTION

This invention relates generally to the art of devices for preventingthe spread of fire through plumbing pipes of buildings, and moreparticularly, to the art of fire-stop collars for surrounding pipes atwall barriers.

For a number of years, pipe networks which have extended through floorsof buildings have been made fire retardant by encircling individualpipes with fire-stop intumescent material which expands upon contactwith heat to close off pipe openings in the floors. It has beensuggested to encircle such an intumescent collar with a container formedof a metallic band and then to attach the metallic container to a bottomsurface of a floor through which the pipe passes. However, difficultiesin accomplishing this have been encountered with prior-art arrangementsbecause the intumescent material must often be installed at a differenttime from the pipe, sometimes being put in place after the pipe has beenextended through holes in floors. The main difficulty in carrying outsuch a procedure is that prior-art fire-stop intumescent materialcollars have had to be formed at job sites, which has been inconvenientand time consuming for workman. It is therefore an object of thisinvention to provide a method for constructing a fire-stop collarassembly, at a factory which can be mounted on a pipe string at aseparate installation site after the pipe has been assembled.

A suggestion has been made for producing a fire-stop pipe couplingadaptor at a factory which includes a pipe coupling having a fire-stopcollar and metallic band wrapped thereabout. This fire-stop pipecoupling adaptor is to be used with a coupler which is cast into a wallbarrier of a building. After a concrete wall barrier has cured with acast-in coupler molded therein a male coupling member of the pipecoupling of the adaptor is inserted into one end of the cast-in couplingand radial tabs of the metallic band of the adaptor are then attached tothe concrete wall barrier so as to hold the adaptor against the barrierat the cast-in coupling. A further pipe is then mounted to an outsideend of the pipe coupling of the fire-stop pipe coupling adaptor. Thisfire-stop pipe coupling adaptor has many advantages, however, it doeshave some disadvantage. One disadvantage is that it requires additionalwork by a plumber, first attaching the adaptor to the cast-in couplingand then attaching a pipe to the adaptor. Also, such a fire-stop pipecoupling adaptor is not sufficiently flexible in use in that it can onlybe installed before a pipe string has been attached to a cast-incoupling. In this regard, sometimes it is desireable for a plumber toinstall a pipe string and then later install an intumescent collar.Thus, it is an object of this invention, to provide a method forconstructing a fire-stop collar assembly which does not require an undueamount of work by a plumber to install and which can be installed eitherbefore or after a pipe string has been attached to a cast-in coupling.

Yet another difficulty with the prior-art fire-stop pipe couplingadaptor described above is that it comprises a special pipe coupling andis thereby somewhat expensive to produce. Thus, it is an object of thisinvention to provide a method for constructing a pipe-stop collarassembly which can be used with standard pipe.

It is a further object of this invention, to provide a method ofconstructing a fire-stop collar assembly which is relatively easy andrelatively inexpensive to carry out and which thereby producesrelatively inexpensive fire-stop collar assemblies.

It is a further object of this invention to provide a fire-stop collarassembly which is extremely easy to install and which can be installedquickly by normally trained plumbers.

SUMMARY OF THE INVENTION

According to principles of this invention, a method of constructing afire-stop collar assembly at a factory separate from an installment sitefor engagement with a pipe at the installment site comprising the stepsof wrapping an intumescent collar and a metallic band about a dummy pipeand, after fastening the metallic band into a ring so as to hold thefire-stop collar assembly together, sliding the dummy pipelongitudinally from the intumescent collar and the metallic band so asto leave the intumescent collar and metallic band as the fire-stopcollar assembly. The fire-stop collar assembly is then transported fromthe factory to be delivered to the separate installment site for beingmounted on a pipe thereat. One embodiment of the invention involvesmaking the intumescent collar of two layers of intumescent materialwhich are glued to one another with glue that cures while theintumescent material is wrapped about the dummy pipe. In thisembodiment, the intumescent collar is also glued to the metallic bandand is longitudinally cut along two break lines which are separated byabout 180°, one of the break lines being at the ends of the metallicband and the metallic band being fastened together by a strap clamp.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of a preferred embodiment of the invention, as illustratedin the accompanying drawings in which reference characters refer to thesame parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingprinciples of the invention in a clear manner.

FIG. 1 is an exploded isometric view of a fire-stop collar assemblyconstructed by a method of this invention illustrating various steps ofthe method and also including thereon a dummy pipe used in the method;

FIG. 2 is a side, partially cutaway, view of the fire-stop collarassembly of FIG. 1 mounted on the dummy pipe;

FIG. 3 is an isometric exploded view of the apparatus of FIGS. 1 and 2showing a further step in the method of invention;

FIG. 4 is an isometric view of another embodiment of a fire-stop collarassembly constructed by the method of this invention; and

FIG. 5 is a top, partially exploded view of the apparatus of FIG. 4illustrating the construction of the assembly of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, the construction of a fire-stop collar assembly 10,is carried out at a factory, the first step of a process therefor beingto choose a cylindrically-shaped dummy pipe 12 having an outer surface14 which is the same size, or slightly larger than, an outer surface ofa pipe on which the fire-stop collar 10 is to be mounted at aninstallment site. In this respect, the dummy pipe 12 can actually be apipe of the type on which the fire-stop collar assembly 10 is to bemounted but in one embodiment, it is a solid cylinder having an outersurface 14 which is slightly larger than a pipe on which the fire-stopcollar assembly 10 is to be mounted.

Once the dummy pipe 12 is selected, inner and outer intumescent bands 16and 18 are cut and wrapped thereabout as is shown in FIG. 1 so as toproduce tightly wrapped inner and outer, substantially-closed,intumescent rings 20 and 22 each having abutting ends 24 and 26 so as toform longitudinal cut, or break, lines 28 and 30 in the intumescentrings 20 and 22. Thereafter, or simultaneously therewith, a metallicband 32 constructed of sheet metal is wrapped about an intumescentcollar 34 formed by the intumescent rings 20 and 22 and first and secondend portions 36 and 38 of the metallic band 32 are caused to overlap asthe metallic band 32 is pulled tightly about the intumescent collar 34and the dummy pipe 12. In this regard, this operation is carried out ina press which tightly compresses the intumescent rings 20 and 22 againsteach other and the intumescent collar 34 against the dummy pipe 12. Inthis embodiment, the length of the intumescent bands 16 and 18 are suchthat their abutting ends 24 and 26 are pressed tightly against eachother so as to hold the intumescent rings 20 and 22 in their circularconfiguration, resisting radially inwardly forces of the metallic band32. Once the metallic band 32 is sufficiently tightly pulled about theintumescent collar 34 and the dummy pipe 12, screws 40 are insertedthrough holes in the first and second end portions 36 and 38 of themetallic band 32 so as to hold the metallic band 32 in a ring about theintumescent collar 34 and to provide these members with fixed diameters.It should be noted that the screws 40 not only extend through the firstand second end portions 36 and 38 of the metallic band 32 but alsoextend into the intumescent collar 34 to further hold the intumescentcollar 34 against longitudinal movement within the ring 42 formed by themetallic band 32.

It can be seen in FIG. 1 that before the above-described steps arecarried out, the metallic band 32 is pre-shaped to form a substantiallyrectangular tape portion 44 having a width which is approximately equalto the width of the intumescent bands 16 and 18. Extending from a bottomedge 45 of the tape portion 44 are heat-transfer tabs 46 and extendingfrom a top edge of the rectangular-shaped tape portion 44 are muchlonger attachment tabs 48 having holes 50 therein Once the metallic band32 is wrapped about the intumescent collar 34 so as to form the metallicring 42, the heat-transfer tabs 46 are bent radially inwardly, to bebelow the intumescent collar 34. These heat-transfer tabs 46 aid inholding the intumescent collar 34 in the metallic ring 42 but yet thereare spaces therebetween to allow heat from a fire below the fire-stopcollar assembly 10 to readily reach a lower edge 52 of the intumescentcollar 34. Further, the heat-transfer tabs 46 conduct heat to the restof the metallic ring 42 to thereby heat a radially-directed outersurface of the intumescent collar 34 for causing the intumescent collar34 to swell, thereby closing off an opening through a barrier to whichthe attachment tabs 48 are attached With regard to the attachment tabs,once the fire-stop collar assembly 10 is ready for use, these tabs arebent radially outwardly, and rivets, screws or other such fasteners aredriven through the holes 50 into a barrier to attach the fire-stopcollar assembly 10 to the barrier.

In the embodiment of FIGS. 1-3, the heat-transfer tabs 46 are actuallylonger than the thickness of the intumescent collar, so that they extendradially inwardly beyond an inner diameter of the intumescent collar 34.With the heat-transfer tabs 46 extending inwardly beyond an innersurface of the intumescent collar 34, it is only possible to apply thefire-stop collar assembly 10 to the end of a female coupler so thatthese heat-transfer tabs 46 extend over the end of the female couplerwhile not interfering with a male pipe being placed into the femalecoupler. However, the tabs could be made shorter so that the fire-stopcollar can be applied to any pipe at any position along the pipe.

In any event, with reference to FIG. 3, once the fire-stop collarassembly 10 is fabricated as described above, opposite forces areapplied to the dummy pipe 12 and to the fire-stop collar assembly 10 sothat the dummy pipe 12 is slid longitudinally upwardly, relative to thefire-stop collar assembly 10, out of the intumescent collar, therebyleaving the fire-stop collar assembly 10 as an integral unit heldtogether by static forces produced by the metallic ring 42 and theintumescent collar 34.

All of the above steps, with the possible exception of theattachment-tab bending steps, are carried out at a factory, separatefrom an installment site. The fire-stop collar assembly 10 is thentransported away from the factory for eventually being transported to aninstallment site where it is longitudinally slid on a pipe couplingwhich is then, or which has already been, positioned adjacent to a wallbarrier as part of a pipe string passing through the wall barrier. Theattachment tabs 48 which have now been radially bent, are then attachedto the wall barrier to hold the fire-stop collar assembly 10 in positionthereagainst.

Again, the heat-transfer tabs 46 can be shorter than the thickness ofthe intumescent collar 34, in which case, the fire-stop collar assemblycan be mounted on a pipe which is the same size as the dummy pipe 12 atany point along the pipe. Because the dummy pipe 12 is slightly largerthan, or approximately the same size as, a pipe on which the fire-stopcollar assembly is mounted at an installment site, the fire-stop collarassembly 10 fits the pipe (the word "pipe" also including a coupler) onwhich it is mounted at the installment site, quite tightly, and a forceis required to insert, or slide, the pipe lengthwise, at the installmentsite, into the fire-stop collar assembly 10; or vise versa, i.e. slidecollar over pipe.

In the FIGS. 1-3 embodiment, the cut, or break, lines 28 and 30 of theintumescent band 16 and 18 do not need to be oriented to coincide withone another nor do they need to coincide with the first and second endportions 36 and 38 of the metallic band 32 forming the metallic ring 42.In fact, it is preferable that none of these ends be adjacent oneanother so that the whole assembly remains together without having aparticular weak area. In this respect, although the intumescent collar34 is constructed of two intumescent bands 16 and 18 or layers, in thisembodiment, it is not necessary for these layers to be glued together orfor them to be glued to the metallic band 32. Once the screws 40 areused to attach the end portions 36 and 38 of the metallic band 32, andthereby form the metallic ring 42, all of the members of the assemblyare held as a unit by internal static forces, even after the dummy pipe12 is removed.

This method of manufacturing can also be used for manufacturing thefire-stop collar assembly 54 of FIG. 4. In this case, the method alsoinvolves wrapping the intumescent bands 16 and 18 as well as themetallic band 32 about the dummy pipe 12. However, the method of makingthe fire-stop collar assembly 54 involves holding the ends 36 and 38 ofthe metallic ring 42 together by means of a surrounding strap clamp 56,which is basically an automobile hose clamp having a worm-tightener 58.The strap clamp 56 encircles the metallic ring 42 in this case, and istightened by the worm tightener 58 so as to compress the metallic ring42 and the intumescent bands 16 and 18 on the dummy pipe 12.

However, there are additional steps that are carried out in themanufacture of the fire-stop collar assembly of FIGS. 4 and 5. That is,before the strap clamp 56 is used to compress the metallic ring 42 andthe intumescent bands 16 and 18 on the dummy pipe 12, glue is placedbetween an outer surface of the intumescent band 18 and an inner surfaceof the metallic ring 42 and glue is applied between the intumescentbands 16 and 18. Also, in manufacturing the embodiment of FIGS. 4 and 5,there are two break lines 60 and 62 made in the outer intumescent band18 and there are two longitudinal break lines 64 and 66 made in theinner intumescent band 16. It should be noted that the longitudinalbreaks, or cuts, 64 and 60 of the intumescent ring 68 and 70 arecoincident with one another and that the break lines 62 and 66 of therespective outer and inner intumescent rings are also coincident.Further, it should be noted that the break lines 60 and 64 of the innerand outer intumescent rings 68 and 70 are approximately 180°. from thebreak lines 62 and 66 of the outer and inner intumescent rings 68 and 70and that the break lines 62 and 66 are approximately coincident with thefirst and second end portions 36 and 38 of the metallic ring 42.

Once the glue has cured, the strap clamp 56 can be loosened and thefire-stop collar assembly 54 can be removed from the dummy pipe 12 bysliding the dummy pipe out longitudinally as is shown in FIG. 3. Butwith this embodiment, it is also possible to completely release thestrap clamp 56 and then pivot opposite sides 72 and 74 of the assemblyopen about a hinge line 76. The hinge line 76 is formed by a bend in themetallic ring 42. When the sides 72 and 74 are hinged away from oneanother, as is shown in FIG. 5, opposite sides of the intumescent rings68 and 70 approximately retain their circular shape and size becausethey are formed by three layers which are glued together, the metallicring and the two intumescent bands.

In any case, once the fire-stop collar assembly 54 is removed from thedummy pipe 12 at a factory, either longitudinally or laterally, it isthen transported away from the factory to eventually be transported toan installment site where it is placed on a pipe having an outerdiameter which is approximately the same as the outer diameter of thedummy pipe 12. With the FIGS. 4 and 5 embodiment, this can beaccomplished either by inserting the pipe longitudinally into a bore 78of the fire-stop collar assembly 54 or by releasing the strap clamp 56,hinging opposite sides 72 and 74 of the assembly apart, manipulating thefire-stop collar assembly 54 so that a pipe on which it is to be mountedpasses through an opening 80 between the opposite sides 72 and 74 andthen again closing the end portions of the strap clamp 56 to bring thefirst and second end portions 36 and 38 together to hold the fire-stopcollar assembly 54 tightly on the pipe. The attachment tabs 48 areattached to a barrier through which the pipe on which the fire-stopcollar assembly 54 is mounted.

The embodiment of FIGS. 4 and 5 has the obvious advantage that it can bemounted on a pipe string after the pipe string has already beeninstalled because its opposite sides 72 and 74 of its assembly can behinged apart to create the lateral opening 80 for allowing it to beplaced on a pipe. The glue which was placed between the intumescentrings 68 and 70 and between the outer intumescent ring 70 and themetallic ring 42 holds all of these member in their proper size andshape and holds them all together when they are "opened up" as is shownin FIG. 5 for mounting them on a pipe. It is advantageous that anintumescent collar 82 of the FIG. 5 embodiment is constructed of twointumescent bands 16 and 18 because this allows greater flexibility forshaping these members about the dummy pipe 12, but yet after the partsare glued together, creates internal forces which cause them to holdtheir sizes and shapes.

While the invention has been particularly shown and described withreference to preferred embodiments, it will be understood by thoseskilled in the art, that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention.For example, it would be possible to glue all of the various layers ofthe apparatus of the FIGS. 1-3 embodiment together. Further, it shouldbe appreciated that a smaller dummy pipe 12 can be used in the FIG. 4-5embodiment than in the FIG. 3 embodiment inasmuch as the diameter of thefire-stop assembly of FIG. 3 cannot be increased for mounting theassembly on a pipe whereas the fire-stop collar assembly 54 of the FIGS.4 and 5 embodiment can have its diameter increased for placing it on apipe string and thereafter decreased for holding it tightly on the pipestring. Also, it would be possible to practice this invention with anintumescent collar of one or more layers.

The embodiments of the invention in which an exclusive property orprivilege are claimed are defined as follows:
 1. A method ofconstructing a fire-stop collar assembly at a factory separate from aninstallment site for permanent engagement on a pipe at said installmentsite, said method comprising the steps of:at said factory, choosing adummy pipe having an elongated cylindrically-shaped main body with anouter surface having an approximate size and shape of a pipe at saidinstallment site on which said fire-stop collar assembly is to bemounted; at said factory wrapping an intumescent band into anapproximate ring about the outer surface of said cylindrically-shapedmain body so as to have ends abutting one another, said intumescentcollar being constructed of a material which expands when it gets hot toclose off the inner surface of said pipe at said installment site onwhich said fire-stop collar will be mounted; at said factory, wrapping ametallic band into a ring with overlapping ends about the intumescentcollar while said collar is wrapped about said dummy pipe, said metallicband having one heat receiving edge at a first end thereof; at saidfactory, applying a fastening means to said metallic band for holdingsaid metallic band in a ring about said intumescent collar while saidintumescent collar is wrapped about said dummy pipe; at said factory,removing said dummy pipe from said intumescent collar and said metallicband while leaving the rings of said intumescent collar and saidmetallic band affixed together by said fastening means to form saidfire-stop collar assembly; transporting said thusly assembled fire-stopcollar assembly from said factory to be delivered to said separateinstallment site for engagement on said pipe thereat; thereby forming afire-stop collar assembly at said factory separate from said installmentsite which is then shipped and stored as a unit and which can be laterplaced on a pipe of a pipe string at said installment site and themetallic band can be attached to a barrier wall thereat to form a fireproof pipe string through said barrier wall.
 2. A method as in claim 1,wherein said fastening means applied includes a plurality of elongatedfasteners extending through ends of the metallic band into theintumescent collar.
 3. A method as in claim 2 wherein the intumescentcollar is constructed of two intumescent band layers which are not gluedto one another and which are not glued to the metallic band.
 4. A methodas in claim 1 wherein the intumescent collar is constructed of twointumescent band layers which are not glued to one another and which arenot glued to the metallic band.
 5. A method as in claim 1 wherein saidfastening means is a strap clamp.
 6. A method as in claim 5 wherein saidintumescent collar is glued to the metallic band and is made to have twolongitudinal break lines, one at end portions of the metallic band andthe other being opposite thereto so that the strap clamp can be removedand the metallic band can be opened at one break line with the metallicband bending at the other break line to allow opposite parts of thefire-stop collar assembly to hinge from one another.
 7. A method as inclaim 6 wherein said intumescent collar is constructed by gluing twointumescent band layers together and wherein the intumescent collar isitself glued to the metallic band.
 8. A method as in claim 1 whereinsaid intumescent collar isglued to the metallic band and is made to havetwo longitudinal break lines, one at end portions of the metallic bandand the other opposite thereto so that the strap clamp can be removedand the metallic band can be opened at one break line with the metallicband bending at the other break line to allow opposite halves of thefire-stop collar assembly to hinge from one another.